High speed photo-electric rotary sequential switch



Nov. 15, 1966 A. FlNLAY 3,286,096

HIGH SPEED PHOTOELECTRIC ROTARY SEQUENTIAL SWITCH Filed Feb. 4, 1964 2. Sh ets-Sheet 1 INVENTOR.

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Nov. 15, 1966 A. FINLAY 3,286,096

HIGH SPEED PHOTO-ELECTRIC ROTARY SEQUENTIAL SWITCH Filed Feb. 4, 1964 2 SheetsSheet 2 United States Patent 3,286,096 HIGH SPEED PHOTO-ELECTRIC ROTARY SEQUENTIAL SWITCH Alexander Finlay, Springfield, Ill., assignor to Sangamo Electric Company, Springfield, 11]., a corporation of Delaware Filed Feb. 4, 1964. Ser. No. 342,457 6 Claims. (Cl. 250-208) This invention relates to a photo-electric rotating switch device and has as its general object to provide a device capable of switching a large number of information channels sequentially at high speed.

Prior art mechanical switches have had limited life, are seriously limited in speed of operation, require excessive maintenance, are unsuited to the switching-of low voltages and introduce noise in electronic circuitry. Prior art capacitor switches have possessed advantages over mechanical switches, but are limited to the switching of AC. signals.

In accordance with this invention, a photo-electric rotary switch is obtained which allows the switching of a large number of signals, either AC. or D.C., in a minimum of space, at a high switching rate and has a long operating life.

A feature of a rotary switch comprising the invention is that a plurality of photocells or photo-duo-diodes arranged in a circle about a light source act as switches when illuminated successively through an aperture in a rotating drum or baflle. The diodes are mounted within the wall of a stationary cylinder with a light sensitive area of each exposed through an opening in the inside wall of the cylinder. A second cylinder or drum whose outside diameter is slightly smaller than the inside diameter of the first cylinder is rotatably mounted coaxial to the first cylinder and contains one or more openings or apertures through which light passes from a source located on the axis of rotation. The second cylinder or drum is mounted on the same shaft as a driving motor. This shaft may also carry the armature of a 3-phase generator to produce a sweep signal when the output is to be displaced on a cathode ray tube.

A further feature of the invention is the improved switching operation which is achieved by a unique arrangement of the photo-duo-diodes and the apertures in the rotating drum whereby it is possible to produce, for example, two complete cycles per revolution of the drum and permit direct drive from the motor which rotates at one-half revolution per switching cycle. The arrangement not only simplifies construction, but permits greater accuracy than would be possible if gear speed changers were interposed between the driving motor and the rotating drum. The arrangement consists of having onehalf of the diodes in one plane perpendicular to the axis of rotation and extending through 180 of the circumference While the other half of the diodes are in another plane likewise perpendicular to the axis of rotation of the drum and extending over the other =180 of the circumference. The rotating drum which surrounds the light source and acts as a baffle to separate it from the openings to the diodes, has four apertures, two apertures in each of the planes of the diodes at 180 from each other. The apertures in one plane are displaced from the apertures in the other plane by an angle of rotation equal to one-half of the angular displacement between two adjacent diodes. The arrangement of the diodes also can comprise other fractions of a circle so that, with a corresponding increase in the number of locating planes therefor and scanning apertures in the rotating drum, other numbers of switching cycles per revolution of the motor can be obtained.

3,286,096 Patented Nov. 15, 1966 ice Still another feature and/ or advantage obtainable with the present invention is that the size of the light apertures in the rotating drum may be such as to provide interpolation between adjacent diodes, that is, so that the signal from one diode may decrease as the signal from a successive diode is increased and without an oil? position. In this case with the signals of two successive diodes equal, the signal output of the switch would not vary between the two positions.

A further use of the present invention would be a converse operation where a single signal would be successively transmitted to a number of circuits so as to successively trigger or operate a plurality of devices.

A better understanding of the invention may be had from the following detailed description thereof taken in connection with the attached drawings, in which:

FIGURE 1 is a vertical sectional view taken through one embodiment of the invention to show arrangement of parts, portions thereof being shown in full for convenience and clarity of illustration;

FIGURE 2 is a sectional view taken along lines 2-2 of FIGURE 1 looking in the direction indicated by the arrows, the cover, light bulb supported thereby and rotating scanning drum being removed, and portions of the electric circuit shown schematically, again for convenience and clarity in showing details in construction of the illustrated embodiment;

FIGURE 3 is a vertical sectional view taken through the stationary cylinder in which the photo-duo-diodes are mounted, the view being taken along lines 3-3 of FIG- URE '2 and looking in the direction indicated by the arrows;

FIGURE 4 is a horizontal sectional view taken through the scanning drum or baffle along lines 44 of FIGURE 5 looking in the direction indicated by the arrows;

FIGURE 5 is a vertical sectional view taken through said scanning drum or bafile along lines 55 of FIGURE 4 looking in the direction indicated by arrows; and

FIGURE 6 is a schematic view which illustrates the angular relation of the apertures in the scanning drum to the two planes of photo-duo-diodes and the sequence in which said diodes are illuminated through the apertures of the scanning drum.

Referring now more specifically to the several views wherein like parts are identified by like reference numerals, and first to FIGURE 1, a preferred embodiment of the invention is illustrated as comprising a housing indicated generally at 10 which includes a base 12 and an enclosing cover 14. At 16 is a stationary cylinder permanently secured to base 12 as by bolts 18. As shown in FIGURE 2, stationary cylinder 16 is provided with a plurality of horizontally disposed equally spaced, radially extending openings or cells 20 of generally cylindrical shape opening through the outer peripheral wall of said cylinder, each having their inner end communicating with the interior of the cylinder through a reduced aperture 22 in the inner peripheral wall of the cylinder. Openings 20 serve as seats in which are mounted photo-duo-diodes 24 or other devices having an electrode sensitive to light to permit or inhibit the fiow of current through a circuit into which said device is connected. In the illustrated embodiment of the invention diodes 24 and seats 20 therefor are shown as comprising forty-eight in number. However, any other number of such diodes may be utilized depending on circumstance and particular requirements. As is most clearly shown by FIGURE 3, one-half of these cells 20 are arranged in an arc of representing onehalf the cylinder 16 and lie in a horizontal plane defined as A-A. The other half of said cells are arranged in a second arc of 180 which completes the annulus or circle which cylinder 16 comprises and are disposed in plane 3 BB which plane is disposed below plane AA in spaced parallel relation thereto.

Referring again to FIGURES l and 2, about station ary cylinder 16 is an annulus 25 of appropriate insulating material which is spaced off base 12 as by spacer ring 26 and secured to said base as by screws 28 which also pass through said spacer ring 26. At 30, is a collector ring of electrically conductive metal secured to the insulating annulus 25 and in spaced encircling relation about stationary cylinder 16. At 32 and 34 are two rings of spaced binding posts supported on annulus 24 and spaced outwardly from collector ring 30. The number of posts in each ring correspond in number to the number of cells 20 and the diodes 24 mounted therein. Binding posts 32 of the outer ring are each electrically connected by a wire 36 'to one of the two electrodes in a respective diode 24, the other electrode of each said diodes being electrically connected by a wire 38 to the adjacent one of the binding posts 34 comprising the inner ring. Each said inner bind ing posts 34 in turn is connected to the aforementioned collector ring 30 by a third wire 40 which includes a resistor 42 for current limiting purposes. Collector ring 30 therefore serves as a common connector to one side of each said diodes 24 and in turn is connected by lead wire 44 to binding post 45 located in one corner of base 12 (FIGURE 2). Thus each said diodes 24 are adapted for connection into respective circuits by connecting one side of the circuit to terminal post 45 as through wire 46 including resistor 47. The other side of such circuit would be connected to one of said outer rings of binding posts 32 as by Wire 48. An opening is provided at 49 in base 12 through which wire 46 may be passed for connection to terminal post 45. At 50 are a pair of openings through base 12 and insulating annulus 24 through which lead wires 48 from each of binding posts 32 may be passed. As previously suggested, the photo'diodes 24 are of the type having an electrode which when exposed to light radiations allows electrons to flow between its two electrodes. The photo-diodes therefore act as normally open switches in their respective circuits which close during the interval when said one of their two electrodes is illuminated. Thus, in accordance with the invention a lamp bulb 52 is supported within the bore of cylinder 16 by mounting device 53 of cover 14 so that diodes 24 when mounted within cells 20 will have at least their light sensitive electrode aligned with the filament of said bulb 52 through the reduced aperture 22 at the inner end of said cells 20. Thus each diode 24 is arranged to receive light radiations from bulb 52 and be energized thereby to activate the circuit into which said diodes are connected in the use of the switching device.

As shown best in FIGURE 1, at 54 is a drum or cup of light occluding opaque material supported on shaft 56 of synchronous motor 58 to turn with rotation thereof, the outer casing of motor 58 being shown bolted to the underside of base 12 as by screws 60. Turning next to FIG- URE 2, the end of shaft 56 has cutouts 62 which provide a ledge or shelf-like seat on which the depending portion 64 of drum 54 rests. Cutouts 62 also provide a non-circular shape to the portion of motor shaft 56 which protrudes through opening 66 (FIGURE 4) in the bottom wall of cup 56 and which opening 66 is correspondingly shaped so that the cup will turn with the rotation of motor shaft 56. A screw 68 threadedly connected into the end of shaft 56-serves to hold cup 54 in place thereon (FIG- UREjl).

Referring now to FIGURE 1, drum 54 has a diameter nearly equal to that of the bore of cylinder 16 and a height so as to cover apertures 22 to cells 20 in both planes AA and BB (FIGURE 3) so as to prevent the passage of light radiations from lamp 52 which would energize diodes 24, except as permitted by the scanning apertures provided in said drum 54. As shown best by FIGURES 4 and 5, these scanning apertures in the illustrated embodiment of the invention comprise four in number. Two of said apertures 68a and 6817 are located so as to lie in plane AA, when dnum 54 is properly assembled on motor shaft 56 and the other two apertures 70a and 70b are located to lie along plane B.B. As shown in FIGURE 4, the apertures of each plane are disposed diametrically opposite each other but angularly displaced from the apertures comprising the other plane by an angle equal to one-half the spacing of the cells 20 in stationary cylinder 16, or diodes 24 seated therein. For example, when the number of cells or photo-diodes comprise forty-eight in number, their angular displacement considered from axis to axis will be 7 /2 which means that aperture 68a in baffie drum 54 will be displaced from aperture 70a in the plane B-B by 345. Similarly, apertures 68b and 7011 will be angularly displaced from each other by said 345, although 180 from apertures 68a and 70a respectively.

Referring therefore now to FIGURE 6, by such arrangement it will be seen that as drum 54 is rotated, diodes 24 will be exposed to radiations from lamp 52 in a regular and predictable sequence. Considering 72 in said FIGURE 6 to represent plane AA and 74 to represent plane B-B in which the diodes 24 are respectively arranged in stationary cylinder 16 and through which scanning apertures 68a, 68b and 70a, 70b, respectively, rotate about axis X withv the energizing of motor 58, it will be apparent that first one diode from the series in plane AA will be illuminated, and then one from the series in plane BB before the next adjacent diode in plane AA will be illuminated. Thus as illustrated in FIGURE 6, aperture 68a in drum 54 isshown aligned with the diode in position 13 so that it is illuminated by radiations from light bulb 52. Said diode lies in plane AA represented by 72. However, since the diodes in plane AA comprise an arc of 180, scanning aperture 6822 does not alignwith any diode. All of the diodes on that side of cylinder 16 lie in plane BB disposed :below plane AA and so cannot receive light radiations through 68b. Moreover, because of the indicated angular displacement of scanning apertures 70b relative to 68b, at the illustrated moment in the rotation of scanning drum 54 its scanning aperture 70b will be directed on a portion of the wall of stationary cylinder 16 between diodes in positions 12 and 14 so again no diode will be illuminated by light radiations passing through aperture 7012. Moreover since scanning aperture a is beyond the arcuate extent of diodes in plane BB, neither will any of the diodes be illuminated by light passing therethrough. Consequently only the diode in position 13 will be energized. However, as scanning drum 54 continues to rotate, aperture 68a will move into the space between cell positions 13 and 15 so that the diode at position 13 will no longer be illuminated and until drum 54 has been turned far enough to align with cell position 15, no diode will be illuminated therethrough. However, in this interval, aperture 70b will have moved from between positions 12 and 14 into alignment with diode position 14 in plane BB so that the diode at said position will be illuminated and aperture 66a will have been moved out of its alignment with position 15. Consequently, since scanning apertures 68b and 70b will be still in the portions of their respective planes not occupied by diodes, only cell 14 will now be illuminated. Thus it will be apparent that as drum 56 continues to rotate it will illuminate each of the cells in the indicated numerical sequence and that by the time it has turned through an arc of it will have permitted illumination of each of the forty-eight cells alternately from the two planes but in the numbered squence. Consequently, upon the completion of one full rotation of drum 54 each of the cells will have been illuminated twice which means that the sequential switches of circuits into which said diodes are connected will have proceeded at a rate twice that a which shaft 56 of motor 58 turns;

It will of course be appreciated that other arrangements can be worked out. For example, the forty-eight cells could be divided into three different planes in each of which planes sixteen cells would be located, each occupying an arc of 120. In such an arrangement the scanning apertures in the rotating drum 54 would be increased so as to comprise three apertures in each of three planes angula'rly displaced 120 apart and correspondingly displaced from those occupying the other two planes so that in sequence, one cell from each plane would be illuminated. This would permit three switching cycles for each revolution or rotation of drum 54.

Many other variations and arrangements of the component parts of the described embodiment of a photoelectric scanning switch in accordance with the invention will at once be apparent and are intended to be included within the broad scope of the invention as is defined by the appended claims. From' the aforesaid description it will be apparent that all of the recited objects, advantages and/ or features for the invention have been demonstrated as obtainable in a device that is exceedingly practical and economical to construct as well as in a device that is extremely accurate and sensitive in its operation.

Thus having described the invention, 1 claim:

1. A photo-electric rotary switch comprising a light source, a plurality of photo sensitive means equally spaced in a-ring about said light source and so as to be illuminated thereby, a fraction of said photo sensitive means being disposed in a first plane and extending through an arcuate portion of said ring, the other of said photo sensitive means being disposed in a second plane parallel to said first plane and extending through a second arcuate portion of said ring, said photo sensitive means being actuated by light radiations so as to act as switches in circuits to which they are connectable, and baffle means rotating about said light source therebetween and the ring of photo sensitive means which inhibit their illumination, said batfie means including two pairs of spaced scanning apertures, one pair being located in said first plane and the other pair in said other plane, the apertures in each plane being angularly displaced from each other and from the apertures in the other plant: by amounts such that each said photo sensitive means is illuminate-d at =least twice in the rotation of said baffle means.

2. A photo-electric rotary switch device comprising a \light source, a plurality of photo-diodes equally spaced in a ring about said light source and so as to be illuminated thereby, a portion of said photo-diodes being disposed in a first plane and extending through an arcuate portion of said ring, another portion of said photo-diodes being disposed in a second plane parallel to said first plane and extending through the remaining arcuate portion of said ring, said photo-diodes beeing activated by "light radiations from said light source so as to act as switches in circuits into which they are connected during use of the device, and bafiie means rotating about said light source therebetween and the ring of photo-diodes which inhibit illumination of said photo-diodes, said baffle means including two pairs of spaced scanning apertures, .one pair being located in said first plane and the other pair in said other plane, the apertures in one plane being angularly displaced from the apertures in the other plane by an angle of rotation equal to one-half the angular displacement between any two of the photo-diodes, and the spacing of the apertures in each of said planes being such that the rotation of said baffie means accommodates sequential illumination of each said photo-diodes.

3. A photo-electric rotary switch scanning device comprising a light source, a plurality of photo-diodes equally spaced in a ring about said light source and so as to be illuminated thereby, said photo-diodes accommodating electron flow only when so illuminated, one-half said photo-diodes being disposed in a first plane and extending through 180 of said ring, the other half said photodiodes being disposed in a second plane parallel to said first plane and extending through the other of said ring, means by which said photo-diodes are connectible into electrical circuits to be controlled thereby, and baffie means rotating about said light source therebetween and the ring of photo-diodes which inhibit illumination of said photo-diodes, said bathe means including two pairs of diametrically opposed scanning apertures, one pair being located in said first plane and the other pair in said other plane, the apertures in one plane being angula-rly displaced from the apertures in the other plane by an angle of rotation equal to one-half the angular displacement between an adjacent pair of the photo-diodes, the rotation of said bathe means serving to sequentially illuminate each said photo-diodes in each one-half rotation of the baflie means.

4. A photo-electric rotary switch scanning device comprising a light source, a plurality of photo sensitive means equally spaced in a ring about said light source and so as to be illuminated thereby, said photo sensitive means being divided into at least two groups each comprising equal numbers of said means, the number of groups being represented by X, each of said groups being disposed in a different plane and which planes are in spaced parallel relation, each said groups of photo sensitive means further extending through an are representing l/X of said ring, each said photo sensitive means accommodating electron flow therethrough when illuminated by said light source, and bathe means rotating about said light source therebetween and the ring of photo sensitive means which inhi-bit illumination of said photo sensitive means, said baffle means containing X groups of spaced scanning apertures, each group being located in a plane corresponding to the plane in which a group of said photocells is arranged, and the apertures in each group being X in number and displaced 360/X apart from each other and each leading a scanning aperture of the group in the next below plane by an angle of rotation equal to l/X of the angular displacement between an adjacent two of the photo sensitive means, the rotation of said bafiie means serving therefore to sequentially illuminate each said photo sensitive means in each l/X rotation of the baffle means.

5. A photo-electric rotary switch scanning device comprising a light source, a plurality of photo diodes equally spaced in a ring about said light source and so as to be illuminated thereby, said photo-diodes being divided into X number of groups, each of said groups :being disposed in a different plane and which are in spaced parallel relation, each group of photo-diodes extending through an arc representing 1/ X of said ring, and baflle means rotating about said light source t-herebetween and the ring of photo-diodes which inhibit illumination of said diodes, said bafiie means including X groups of spaced scanning apertures, each group comprising X apertures and each being located in a plane corresponding to the plane in which a group of diodes is arranged, the apertures in each plane being displaced 360/X apart from each other and from an aperture of a group thereof occupying an adjacent plane by an angle of rotation equal to l/X of the angular displacement between an adjacent two of the photo-diodes, the rotation of said baffle means serving therefore to sequentially illuminate each of said photodiodes in each l/X rotation of the baflie means.

6. A photo-electric rotary switch scanning device comprising, in combination, a plurality of photo cells arranged in a circle, and a 'light source located at the center thereof, said photo cells being divided into groups each occupying a different arcuate portion of said circle, the photo cells of each group being located in the same plane and other than in the plane in which the other of said photo cells are arranged, and battle means rotating within said circle between said photo cells and the light source, said bafiie means including a plurality of scanning apertures arranged in groups corresponding to the planes in which the groups of photo cells are arranged so as to align with References Cited by the Examiner UNITED STATES PATENTS 2,791,724 5/1957 Ekblotrn et a1. 2502O9 5 RALPH G. NILSON, Primary Examiner.

MARTIN ABRAMSON, Assistant Examiner. 

1. A PHOTO-ELECTRIC ROTARY SWITCH COMPRISING A LIGHT SOURCE, A PLURALITY OF PHOTO SENSITIVE MEANS EQUALLY SPACED IN A RING ABOUT SAID LIGHT SOURCE AND SO AS TO BE ILLUMINATED THEREBY, A FRACTION OF SAID PHOTO SENSITIVE MEANS BEING DISPOSED IN A FIRST PLANE AND EXTENDING THROUGH AN ARCUATE PORTION OF SAID RING, THE OTHER OF SAID PHOTO SENSITIVE MEANS BEING DISPOSED IN A SECOND PLANE PARALLEL TO SAID FIRST PLANE AND EXTENDING THROUGH A SECOND ARCUATE PORTION OF SAID RING, SAID PHOTO SENSITIVE MEANS BEING ACTUATED BY LIGHT RADIATIONS SO AS TO ACT AS SWITCHES IN CIRCUITS TO WHICH THEY ARE CONNECTING, AND BAFFLE MEANS ROTATING ABOUT SAID LIGHT SOURCE THEREBETWEEN AND THE RING OF PHOTO 